[ARM] 5613/1: implement CALLER_ADDRESSx

[firefly-linux-kernel-4.4.55.git] / arch / arm / kernel / return_address.c

diff --git a/arch/arm/kernel/return_address.c b/arch/arm/kernel/return_address.c
new file mode 100644 (file)
index 0000000..df246da
--- /dev/null
+++ b/arch/arm/kernel/return_address.c
@@ -0,0 +1,71 @@
+/*
+ * arch/arm/kernel/return_address.c
+ *
+ * Copyright (C) 2009 Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
+ * for Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+#include <linux/module.h>
+
+#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
+#include <linux/sched.h>
+
+#include <asm/stacktrace.h>
+
+struct return_address_data {
+       unsigned int level;
+       void *addr;
+};
+
+static int save_return_addr(struct stackframe *frame, void *d)
+{
+       struct return_address_data *data = d;
+
+       if (!data->level) {
+               data->addr = (void *)frame->lr;
+
+               return 1;
+       } else {
+               --data->level;
+               return 0;
+       }
+}
+
+void *return_address(unsigned int level)
+{
+       struct return_address_data data;
+       struct stackframe frame;
+       register unsigned long current_sp asm ("sp");
+
+       data.level = level + 1;
+
+       frame.fp = (unsigned long)__builtin_frame_address(0);
+       frame.sp = current_sp;
+       frame.lr = (unsigned long)__builtin_return_address(0);
+       frame.pc = (unsigned long)return_address;
+
+       walk_stackframe(&frame, save_return_addr, &data);
+
+       if (!data.level)
+               return data.addr;
+       else
+               return NULL;
+}
+
+#else /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) */
+
+#if defined(CONFIG_ARM_UNWIND)
+#warning "TODO: return_address should use unwind tables"
+#endif
+
+void *return_address(unsigned int level)
+{
+       return NULL;
+}
+
+#endif /* if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND) / else */
+
+EXPORT_SYMBOL_GPL(return_address);